1. Field of the Invention
The present invention relates to a novel reagent for analysis of hydrogen peroxide, a method of analysis of hydrogen peroxide using the same, a method of analysis of peroxidase using the same, and a multilayer chemicalanalytical element containing the same. More particularly, the present invention relates to a novel color forming compound which is capable of forming a color in the presence of hydrogen peroxide and a catalytic substance having an oxidizing activity, such as peroxidase, a method for colorimetric quantitative analysis of hydrogen peroxide using the same, and a multilayer chemical-analytical element which contains the same and is suitably employable in quantitative analysis of hydrogen peroxide or an analyte (substance to be analyzed) capable of forming hydrogen peroxide, as well as in quantitative analysis of peroxidase activity.
2. Description of Prior Arts
Enzymic analytical methods in clinical test have been highly valued in their specific reactivity and have rapidly come into wide use in recent years. Particularly, in quantitative analyses of glucose, uric acid, cholesterol, triglyceride, lactic acid, creatinine, free fatty acid, glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, cholinesterase, creatine phosphokinase and lactate dehydrogenase in body fluid and urine, there are frequently used methods of quantitatively analyzing such object (analyte) by causing said analyte or a final intermediate product derived from the analyte to react with an oxidase therefor and determining thus produced hydrogen peroxide.
As the methods of quantitative determination of hydrogen peroxide, there are known, for example, methods disclosed in the specifications of Japanese Patent Provisional Publication Nos. 50(1975)-115892, 53(1978)-110897, 54(1979)-25892, 55(1980)-20471, 55(1980)-92696, 55(1980)-121149, 55(1980)-131400, 56(1981)-37557, 56(1981)-39072, 56(1981)-42599, 57(1982)-142562, 57(1982)-150399, etc. These specifications disclose colorimetric methods comprising converting a chromogen such as o-tolidine, 2,7-diaminofluorene, N,N-dimethyl-p-phenylenediamine, o-dianisidine or o-aminophenol into a colored substance through oxidation, as well as colorimetric methods comprising converting a chromogen such as a combination of 4-aminoantipyrine with phenol, N,N-dialkylaniline or N,N-dialkyltoluidine, a combination of 3-methyl-2-benzthiazolinone hydrazone with o-tolidine, N,N-dimethylanline or N,N-diethylaniline, or 4-methoxy-1-naphthol capable of forming a dimer or its derivative into a colored substance by oxidative condensation.
The methods using these compounds are disadvantageous in determination of minor constituents (analyte), since these compounds require two molar hydrogen peroxide to form one molar colored substance (dye). For this reason, a reagent for quantitatively analyzing hydrogen peroxide, which requires only one molar hydrogen peroxide to form one molar dye is desired.
The inventor has already investigated such a reagent for analysis of hydrogen peroxide, which comprises an imidazole derivative having the formula (I): ##STR2## wherein R.sup.1 is an aryl group substituted with hydroxyl group at the ortho- or para-position, R.sup.2 is an unsubstituted or substituted aryl group, and R.sup.3 is an unsubstituted or substituted alkyl or an unsubstituted alkenyl group, the method of analysis of hydrogen peroxide using the same, the method of analysis of peroxidase using the same, and a multilayer chemical-analytical element containing the same (U.S. patent application Ser. No. 6/601,632).